User Configuration > Administrative Templates > Microsoft Visio 2016 > Visio Options > General > User Interface Options
User
HKCU\software\policies\microsoft\office\16.0\visio\application
This policy setting turns off the Live Preview in the Shapes window feature, which shows shapes in the Shapes window with the detail and color depth they will have in a drawing, including theme colors and effects. If you enable this policy setting, Live Preview in the Shapes Window is turned off. If you disable or do not configure this policy setting, Live Preview in the Shapes Window is turned on.